#include "gbos.h"
/* uniq [-c] [file]: collapse runs of identical ADJACENT lines (like uniq(1) -
 * it does not sort). -c prefixes each line with how many times it repeated. */

#define MAXLINE 80

static unsigned char lines_eq(const char *a, unsigned char la, const char *b, unsigned char lb) {
    unsigned char i;
    if (la != lb) return 0;
    for (i = 0; i < la; i++)
        if (a[i] != b[i]) return 0;
    return 1;
}

void main(void) {
    char *argv[4];
    char cur[MAXLINE], prev[MAXLINE];
    unsigned char argc = argv_parse(argv, 4);
    unsigned char cnt = hasflag(argv, argc, 'c');
    unsigned char clen = 0, plen = 0, have = 0, fd = NOFD, i;
    unsigned int reps = 0;
    char *fname = 0;
    int ch;

    for (i = 0; i < argc; i++)
        if (argv[i][0] != '-') {
            fname = argv[i];
            break;
        }
    if (fname) {
        fd = open(fname, O_READ);
        if (fd == EISDIR) {
            puts("uniq: is a directory");
            nl();
            sexit(2);
        }
        if (fd == NOFD) {
            puts("uniq: no such file");
            nl();
            sexit(2);
        }
    }
    for (;;) {
        if (fd == NOFD) {
            char c = readc();
            ch = (c == EOF) ? -1 : c;
        } else ch = fgetc(fd);
        if (ch == '\r') continue;
        if (ch >= 0 && ch != '\n') {
            if (clen < MAXLINE) cur[clen++] = (char)ch;
            continue;
        }
        /* EOF with nothing buffered: stop. Falling through would compare an
           empty "line" against the last run and flush a phantom blank one -
           which showed up as a stray "1" in uniq -c. */
        if (ch < 0 && clen == 0) break;
        if (have && lines_eq(cur, clen, prev, plen)) reps++;
        else {
            if (have) { /* flush the run that just ended */
                if (cnt) {
                    putu(reps);
                    putc(' ');
                }
                writes(prev, plen);
                nl();
            }
            for (i = 0; i < clen; i++) prev[i] = cur[i];
            plen = clen;
            have = 1;
            reps = 1;
        }
        clen = 0;
        if (ch < 0) break;
    }
    if (have) {
        if (cnt) {
            putu(reps);
            putc(' ');
        }
        writes(prev, plen);
        nl();
    }
    if (fd != NOFD) close(fd);
}